1. Field
The following description relates to a magnetic sensor and a method of fabricating the same, and to a magnetic sensor including hall elements and an integrated magnetic concentrator (IMC) that may detect a direction of a magnetic field and a method of fabricating the same.
2. Description of Related Art
A magnetic sensor is used to detect a magnetic field. A magnetic sensor that combines a hall element and an integrated magnetic concentrator (IMC) may be used to detect a direction of a magnetic field.
In an example of such a magnetic sensor, an IMC is formed of a magnetic material with a flat shape. A hall-effect device is disposed in an edge portion of the IMC of the magnetic sensor. Such a magnetic sensor may be used to detect a direction of a three-dimensional magnetic field.
The magnetic sensor having the configuration is effective in detecting a horizontal magnetic field and amplifying a magnetic field in a region in which the hall-effect device is disposed through the IMC.
FIG. 1 is a plan view illustrating a magnetic sensor disclosed in U.S. Pat. No. 6,545,462. The reference numeral 3 denotes an IMC, and the reference numerals 2.1 to 2.6 denote hall-effect elements.
The magnetic sensor having the configuration as illustrated in FIG. 1 includes an IMC 3 having a flat upper surface and a flat lower surface. The flat shape of the IMC 3 results in high stress to the hall-effect elements 2.1 to 2.6 and causes an offset voltage of the magnetic sensor to increase. Therefore, it is desirable to reduce the stress and to lower the offset voltage of such a magnetic sensor.
In the magnetic sensor of FIG. 1, a voltage of the hall-effect element has to be zero (0) when a magnetic field is not applied. However, the voltage of the hall-effect element may have values other than zero (0). The offset voltage denotes a voltage difference when the voltage of the hall-effect element has values other than zero (0). As the offset voltage increases, malfunction is more likely to occur in the magnetic sensor. Further, when a magnetic field is applied to a device having a large offset voltage, the change in the voltage of the hall-effect element is insignificant and the sensitivity of the device is reduced. In other words, a ratio of signal to noise is reduced because the offset voltage is large. In applications in which fine changes in magnetic field are detected, it is difficult to detect the fine changes with a magnetic sensor having a high offset voltage.